石油污染对土壤微生物群落多样性的影响

Influence of oil pollution on soil microbial community diversity

摘要:

土壤中的微生物主要有细菌、放线菌、真菌三大类群，微生物在石油污染的土壤中发挥着维持生态平衡和生物降解的功能。文中以四川省遂宁市射洪县某废弃油井周围不同程度石油污染土壤为供试土壤，首先对各组供试土壤的基本理化性质进行测定分析；然后采用平板菌落计数法测定了供试土壤中三大类微生物数量的变化，结果表明：相比未被污染的对照土壤，石油污染的土壤中细菌、放线菌、真菌数量均减少，并且土壤中可培养微生物的数量与土壤含水量呈正相关；再采用454焦磷酸测序技术对土壤中的细菌群落多样性及变化进行16S rRNA基因分析。在所有供试的4个土壤样品中，共鉴定出不少于23 982个有效读取序列和6 123种微生物，相比于未被污染的对照土壤，石油污染土壤中细菌的种类更加丰富，主要优势门类为酸杆菌门、放线菌门、拟杆菌门、绿弯菌门、浮霉菌门和变形菌门。但不同土壤样品中优势菌群的群落结构有所差异，石油污染的土壤中，酸杆菌门、放线菌门和变形菌门的数量最多，未被石油污染的土壤中，放线菌门、拟杆菌门和变形菌门的数量最多。

Abstract:

Bacteria, actinomycetes and fungi are the three major groups of soil microbes. Soil microbes play a critical role in ecological and biodegradation processes in petroleum-contaminated soils. Based on the actual situation, this study took the oil polluted soil around the abandoned oil well in Shehong County, Suining City, Sichuan Province as the test soil. First, we determined the physiochemical properties of the tested soil; then we analyzed the changes of physiochemical properties and the three major microbes in petroleum contaminated soils. The number of the three major microbes in contaminated soils was relatively fewer than uncontaminated samples, and the water content of the soil was in positive correlation with the number of microbes. Also we assessed the soil bacteria community diversity and changes therein in petroleum-contaminated soils using 454 pyrosequencing of 16S rRNA genes. No less than 23 982 valid reads and 6 123 operational taxonomic units (OTUs) were obtained from all 4 studied samples. OTU richness was relatively higher in contaminated soils than uncontaminated samples. Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Planctomycetes and Proteobacteria were the dominant phyla among all the soil samples. However, the prokaryotes community abundance of phyla was significantly different in the four samples. The most abundant OTUs associated with petroleum-contaminated soil sample were the sequences related to Acidobacteria, Actinobacteria and Proteobacteria, whereas the most abundance sequences with uncontaminated sample were those related to Actinobacteria, Bacteroidetes and Proteobacteria.